Signal device for food package



Sept. 6, 1960 K. J. CHASE 2,951,754

SIGNAL DEVICE FOR FOOD PACKAGE Filed Jan. 25, 3.957

SIGNAL DEVICE FOR FOOD PACKAGE Kenneth J. Chase, 6 Pine Ridge Road, Reading, Mass.

Filed Jan. 25, 1957, Ser. No. 636,353

3 Claims. (Cl. 99-192) This invention relates towarning or telltale devices operative to inform a user or purchaser of frozen foods whether the food has been thawed in the interval be tween quick-freezing and its purchase.

In my Patent No. 2,460,215, there is shown and described a device which is adapted to be embedded in a package of frozen food which will change color if the package becomes thawed at any time prior to its use to warn the user of this fact. The device has a body portion which extends deeply into the package and a head located adjacent the surface thereof. In the head there is a window and beneath the window there is material which will change color in the presence of moisture. A sealed capsule of water is placed in the body which when frozen as the package is subjected to quick-freezing will burst and hence provide a potential source of water to a wick which extends from the body portion to the head. The material employed in the head of the aforesaid device was permanganate powder and it was found diflicult to avoid a premature color change of the permanganate during manufacture without employing precautions which made the article economically impractical.

Objects of this invention are accordingly to provide a device embodying the beneficial characteristics of the patented telltale without its disadvantages in manufacture, thereby to make it economical and practical. Other objects are to provide a device which will be reliable and will not embody any components which are injurious to the food itself.

As herein illustrated the device has a portion adapted to be buried in the package and a head adapted to be exposed at one surface thereof. Within the device there are two axially arranged chambers, one next to the head and the other inwardly thereof. In the head there is a window and in the chamber behind the window there is disposed of a mass of colorable material, for example, cotton batting, the color of which may be seen through the window. A colorant in the form of a pellet is also disposed in the chamber in contact with the mass, which colorant is releasable so as to impart its color to the mass by means of a suitable activant supplied to it from the inner chamber only when the package thaws, that is rises above freezing. As herein illustrated the colorant is a water soluble dye and will dissolve in the presence of moisture and become disseminated throughout the cotton by capillarity, so as to change theoverall color of the cotton. The activant is water, initially contained within a sealed capsule placed within the inner chamber and upon freezing turns to ice. Expansion of the water during freezing bursts the capsule so that a chunk of ice is exposed therein. As long as the package remains frozen the chunk of ice remains frozen so that no water is available for dissolving the dye and thus changing the color of the cotton. If the package thaws however the chunk of ice melts, thereby providing a source of water and this is conducted by a wick extending from the inner chamher to the cotton in the outer chamber. Optionally the I head 18. .The lower part 32 Patented Sept. 6, 1960 activant may be a volatile substance which will remain capsulated as long as the package is below freezing but which will expand sufliciently upon thawing of the package to burst the capsule and thereby supply the substance to the wick or other conducting means for transmission to the cotton in the outer chamber.

Alternatively the capsulated activant may be omitted, in which case the walls of the inner chamber must be made of a substance which is pervious to water vapor, although not to water as such. As thus constructed if the device is kept refrigerated below freezing for a period of approximately one month ice crystals will gradually accumulate on the inner wall of the inner chamber so that upon thawing a sufficient quantity of water is available to bring about dissolving of the dye and coloration of the cotton.

The invention will now be described in greater detail with reference to the accompanying drawings wherein:

Fig. 1 is a transverse section through a conventional food package showing the warning device installed therein;

Fig. 2 is an elevation of the warning device to larger scale prior to insertion into the package;

Fig. 3 is a top view of the warning device as it appears prior to changing color;

Fig. 4 is a top view of the warning device as it would appear after changing color;

Fig. 5 is a diametrical longitudinal section of Fig. 2 showing the preferred form;

Fig. 5a is a diametrical section transversely of the device taken on the line 5LZ-5L1 of Fig. 5;

Fig. 6 is a plan view of the colorant;

Fig. 7 is an elevation thereof;

Fig. 8 is an elevation of the colorable material with its appendant wick and with the colorant embedded therein, removed from the device;

Fig. 9 is a section of a sealed capsule containing an activator for releasing the color from the colorant;

Fig. 10 is a modification of the device;

Fig. 11 is a fragmentary elevation of a further m'odification in which the walls of the device have narrow slit-like louvres therethrough; and

Fig. 12 is a diametrical section of Fig. 11 taken through one of the louvres.

Referring to the drawings, there is shown in Fig. 1, a mass of quick-frozen food 10 wrapped in a conventional moisture-resistant wrapper 12 and enclosed in an outer box or container 14 of cardboard or the like.

In accordance with the present invention, this package is provided with a signal device S (Figs. 1 and 2) comprising an elongate hollow casing having a body portion 16 adapted to be located within the package and penetrating deeply into the mass of the frozen food and a head portion 18 adapted to be positioned externally of the package so as to be easy to inspect. To facilitate insertion into the package prior to quick-freezing the inner portion 16 is tapered somewhat and has at its inner end a sharply tapering point 20 of cone-shape. The head 18 has a peripheral flange 22 of greater cross-section than the body which provides a shoulder 24 for limiting penetration of the device by contact with the outer wall of the container. An annular bead 26 is formed on the portion 16 which is axially spaced from the flange 22 by approximately the thickness of the container 14, so as to provide an annular groove 28 between it and the flange 22 for receiving the marginal edge of the wall of the container, thereby to hold the device in place.

The casing is comprised of hollow telescoping upper and lower parts 30 and 32 (Fig. 5 The upper part 30 is cylindrical in cross-section and has integral with it the is a segment of a cylinder and has integral with it the point 20, the base of which is of larger diameter than the body and provides an annular shoulder, so that when the parts are assembled the lower open end of the upper part 30 engages the shoulder, thereby holding the inner end of the part 32 spaced from the inside of the head 18. At the inner end of the part 32 there is a circular end wall 34 which divides the interior of the device 16 into twochambers, an upper chamber 38 located next to the head and a lower chamber 40 located interiorly of the lower part 3-2. The end wall 34 of the part 32 has an opening in the form of a hole or notch 42 (Figs. and 5a) so that there is a passage from: the chamber 38 into the cham ber 40.

The head 18 at least of'the part 30 is made of transparent material so that it is possible to see through the headinto the chamber 38-. Preferably both parts 30 and 32 are made of synthetic resins such as styrene which is impervious to water, inert to reaction with the food product and transparent. The two parts are carefully machined so as to fit tightly together and thus to provide a casing which is substantially leak-tight. A sealer or adhesive may be applied to the parts prior to assembly to provide a water-tight seal between the parts so as to prevent access of moisture from the food itself.

In the upper chamber 38 there is placed a mass of material 46 (Fig. 5) which has a predetermined color but is colorabl'e so as to have a distinctively different color. The mass 46 is preferably comprised of a capil- Iary material, for example, a wad or ball of white cotton fibers, although it is to be understood that any other equivalent or similarly acting material may be used. As herein shown, a portion of the wadded cotton is drawn and twisted slightly to form a wick 48' (Figs. 5 and 8), which extends downwardly through the hole 42 into the chamber 40.

The wad of cotton has embedded in it a pellet 50 containing a colorant, for example, a dye, stain or pigment, which may be released therefrom by a suitable activator so as to be taken up by the cotton, the activant being brought to the pellet by the capillary action of the cotton and in turn disseminated throughout the cotton by its capillary action. The pellet as herein illustrated is in the form of a small coil (Figs. 6 and 7) of crepe paper or similar absorbent paper, such as blotting paper which is impregnated with a soluble colorant and then dried, whereupon the pellet is embedded in the cotton. As long as no activant reaches the cotton in the upper chamber 38 the colorant will remain inert.

Within the part 32, that is, in the chamber 40, there is placed a sealed capsule 52 (Fig. 9) of suitable plastic tubing or the like,'which contains an activant. The capsule has thin walls which may be disrupted so as to release the activant and to permit it to be conducted by contact with the wick 48 into the cotton ball in the chamber 38 and hence to the pellet 50, thereby to release the color from the colorant and to permit the latter to impart its color to the cotton. If the colorant is water soluble the activant may be distilled water sealed in the capsule 52. Water is especially suitable because it expands when freezing so that when the device is placed in the package and quick-frozen the expansion of the water bursts the capsule 52, thereby providing an inert supply of water. The small block of ice exposed within the chamber will not wet the wick as long as the temperature of the food package remains below freezing hence no moisture will be conducted by the wick to the pellet 50. If the temperature does rise above freezing the ice melts sufficiently to supply water to the wick which is carried by the capillary action of the wick up to the cotton ball 46 and to the pellet 50 dissolving the. color in the colorant which then spreads through the cotton imparting its color to the cotton so that a different color is seen through the window. Water is the most common substance which expands with freezing,

however, other substances may be used which act the same way-as water, that is, expand on freezing so as to disrupt the capsule thereby providing a solvent or activant of the colorant used in the pellet 50. It is also possibleto use an activant which would burst the capsule by expansion, not upon freezing of the package but upon thawing. Thus for example the capsule may be filled with a highly volatile substance which if kept at a low temperature, will not exert. sufficient pressure to burst the capsule but which will expand if the temperature rises above freezing such as. by thawing of the package to burst the capsule and release the activant. As long as the package remains completely frozen the substance in the capsule will be sealed therein and hence there will be no danger of its reaching the pellet 50, as for example by sublimation so as to change the color even though no thawing has taken place.

It has been found possible to simplify the device under certain conditions by omitting the capsule of activant entirely. When this is done the pellet 50 must contain a water soluble colorant and the walls of the parts 30 and 32 below the end wall 34 of the part 32 must be made of a material which is pervious to water vapor, although not to wateras such. Thus as shown in Fig. 10, the wall portions 30a32a of the parts 30 and 32 are made of' a material which ispervious to water vapor, for example, vinyl acetate. If new the device is driven into a package and the latter is then quick-frozen and stored for a period of approximately a month under freezing conditions a layer of ice crystals will form on the inside of the wall portions 30a-32a. After this if the package is thawed these ice crystals will give up suflicient water to saturate the cotton and release the color from the pellet 50. The quick-freezing results in contraction of the air within the device which produces a somewhat lower pressure therein and it is thought that as a result there is a slow movement of water vapor from the package inwardly through the porous walls into the device in spite of the fact that freezing conditions are maintained continuously. The accumulation while slow is sufficient if the package is kept under refrigeration for approximately a month prior to distribution to retailers so that following distribution if thawing occurs coloration of the cotton will take place. While this simplifies the device and cheapens its construction in that the extra part, to wit, the capsule of activant may be omitted, it requires that the package be kept by the packer and freezer for a months period and this may be wholly undesirable from the standpoint of many packers.

Alternatively, instead of making the walls of the device below the end wall 34 permeable to water vapor they may be made impervious as described with reference to Figs. 1 to 5, and be provided with one or more .slitlike louvres 56, as shown in Figs. 11 and 12. The louvre 56 should be confined to the lower part of the wall below the end wall 34 and if there are several, preferably should be distributed at equal distance from each other about the periphery of the parts. The louvres will, of course, admit moisture in the form of water vapor much faster than the device shown in Fig. 10, so that it. will not be necessary to keep it refrigerated for as long a time before the device will accumulate a suflicient quantity of frost crystals to activate the colorant when subsequent thawing takes place. This modification has the advantage of that shown in Fig. 10, in that a separate capsule of water is not required without the disadvantage of length of time before it becomes operative. More care must be taken however in the use of this device since if the food is not frozen very quickly there is a chance that moisture may leak through the louvres and activate thecolorant before freezing is accomplished.

In use the assembled structure is pushed down into the food package just before the latter is put into the rapid freezing apparatus. The cardboard which forms the outer container of the food package may be provided with a hole to facilitate the introduction of this signal device, although the casing is preferably provided as previously indicated with a sharp point at its lower part to facilitate its introduction into the package. As also previously indicated the device has a circumferential rib which snaps down below the edge of the cardboard and thus helps to hold the device in place. When the food package is subjected to freezing, the capsule containing the water or other substance bursts but since the water is then frozen it does not moisten the wick extending into the chamber containing the cotton and hence the colorant is not activated. If, however, the food package is allowed to defrost, the block of ice or other substance which is frozen will melt and will be conducted by the wick to the cotton in the upper part, whereupon the color will be released and be disseminated throughout the cotton and impart to it a distinctive color which may then be seen through the transparent top of the device,

thus notifying any person examining the package that it has been defrosted. Of course, refreezing does not change this color once it becomes disseminated throughout the cotton so that it serves as an irrefutable warning to the purchaser that the package has, at some time, been defrosted.

As will be seen from the foregoing the device as a whole is inexpensive to manufacture and assemble, since its parts are made of commercially available materials and no special precautions or techniques are required. The pellet 50, as previously indicated, may be a small strip of crepe paper or blotting paper impregnated with a dye. A very satisfactory dye is boiled beet juice which is inexpensive and being a vegetable dye is completely harmless. To make the pellet the absorbent paper may be soaked in the beet juice, dried and cut up into small strips which may then be rolled up between the fingers and will retain the color until released by moisture. The capsule 52 containing the distilled water is made of a suitable plastic and may be manufactured on any commercial machine such as is used for capsulating medicines, vitamins and the like, as is so widely done in the preparation of pharmaceutical preparations.

All of the components are completely harmless to the food and are not affected by the ingredients of the food and so function without fail.

It should be understood that the present disclosure is for the purpose of illustration only and that this invention includes all modifications and equivalents which fall within the scope of the appended claims.

I claim:

1. A warning device for a quick-frozen food package comprising an elongate closed casing having an outer portion located adjacent the outer surface of the package in which there is a window and an inner portion designed to be located deep within the package, a mass of dry absorbent material within the outer portion visible through the window, a body containing a dye consisting of dried vegetable juice embedded in the absorbent material, a wick extending from the absorbent material into the inner portion, and means located in the inner portion for releasing a liquid solvent of the dye when the package rises above freezing for conductance by the wick to the absorbent material to wet the body containing the dried vegetable juice dye embedded therein, to release the latter for spreading by capillarity throughout the wetted mass of absorbent material.

2. In combination with a package of frozen food, an elongate closed casing having a body portion embedded deeply in the package and a head located at the surface of the package, said head having a window therein, a mass of dry absorbent material in the head behind the window, a body containing a dye consisting of dried vegetable juice embedded in the absorbent material adapted when wetted to impart its color to the mass, a conductor extending from the body into the head into engagement with the absorbent material to supply water to the dried vegetable juice dye, and a quantity of ice crystals in the body portion, said crystals being operative to give up water to the conductor when the temperature of the package rises above freezing.

3. A warning device for a quick-frozen food package comprising an elongated body comprised of hollow telescoping parts, said parts having interengaging end portions which hold them axially spaced so that the inner end of one part is spaced from the outer end of the other part, thereby providing a chamber between the inner end of the one part and the outer end of the other part, the inner end of the one part having an opening through it providing a passage from said chamber into the interior of that part, a window in the outer end of the other part, said window constituting a side of the chamber, a wad of cotton in the chamber visible through the window, a body containing a quantity of dried beetjuice embedded in the cotton in the chamber, a portion of the cotton being twisted and drawn through the opening into the one part, and means within the one part operable to supply liquid solvent to the twisted end and hence to the dye in the chamber when the temperature of the interior of the food package rises above the freezing point to dissolve the dye whereupon it disseminates throughout the cotton.

References Cited in the tile of this patent UNITED STATES PATENTS 2,460,215 Chase Jan. 25, 1949 2,490,933 Tornquist et al. Dec. 13, 1949 2,560,537 Andersen July 17, 1951 

1. A WARNING DEVICE FOR A QUICK-FROZEN FOOD PACKAGE COMPRISING AN ELONGATE CLOSED CASING HAVING AN OUTER PORTION LOCATED ADJACENT THE OUTER SURFACE OF THE PACKAGE IN WHICH THERE IS A WINDOW AND AN INNER PORTION DESIGNED TO BE LOCATED DEEP WITHIN THE PACKAGE, A MASS OF DRY ABSORBENT MATERIAL WITHIN THE OUTER PORTION VISIBLE THROUGH THE WINDOW, A BODY CONTAINING A DYE CONSISTING OF DRIED VEGETABLE JUICE EMBEDDED IN THE ABSORBENT MATERIAL, A WICK EXTENDING FROM THE ABSORBENT MATERIAL INTO THE INNER PORTION, AND MEANS LOCATED IN THE INNER PORTION FOR RELEASING A LIQUID SOLVENT OF THE DYE WHEN THE PACKAGE RISES ABOVE FREEZING FOR CONDUCTANCE BY THE WICK TO THE ABSORBENT MATERIAL TO WET THE BODY CONTAINING THE DRIED VEGETABLE JUICE DYE EMBEDDED THEREIN, TO RELEASE THE LATTER FOR SPREADING BY CAPILLARITY THROUGHOUT THE WETTED MASS OF ABSORBENT MATERIAL. 